Environmental contamination and risk factors for transmission of highly pathogenic avian influenza A(H5N1) to humans, Cambodia, 2006-2010

Abstract

BackgroundHighly pathogenic avian influenza A (H5N1) virus has been of public health concern since 2003. Probable risk factors for A(H5N1) transmission to human have been demonstrated in several studies or epidemiological reports. However, transmission patterns may differ according to demographic characteristics of the population and local practices. This article aggregates these data from three studies with data collected in the previous surveys in 2006 and 2007 to further examine the risks factors associated with presence of anti-A(H5) antibodies among villagers residing within outbreak areas.MethodsWe aggregated 5-year data (2006–2010) from serology survey and matched case-control studies in Cambodia to further examine the risks factors associated with A(H5N1) infection among villagers in the outbreak areas.ResultsSerotesting among villagers detected 35 (1.5 % [0–2.6]) positive cases suggesting recent exposure to A(H5N1) virus. Practices associated with A(H5N1) infection among all ages were: having poultry cage or nesting area under or adjacent to the house (OR: 6.7 [1.6–28.3]; p = 0.010) and transporting poultry to market (OR: 17.6 [1.6–193.7]; p = 0.019). Practices found as risk factors for the infection among age under 20 years were swimming/bathing in ponds also accessed by domestic poultry (OR: 4.6 [1.1–19.1]; p = 0.038). Association with consuming wild birds reached borderline significance (p = 0.066).ConclusionOur results suggest that swimming/bathing in contaminated pond water and close contact with poultry may present a risk of A(H5N1) transmission to human.

Factors Influencing Mitigation of Risk of Waterborne Disease in Vietnam Among Small Scale Integrated Livestock Farmers

“…Previous research has shown that agricultural producers including poultry farmers identify animal waste management as important to preventing disease ( 45 , 46 ), particularly where there is contact with water associated with agricultural production ( 16 , 19 , 20 ). Interestingly, we also found consistency in previous research with the perception of many of our respondents that HPAI cannot happen to them ( 27 , 45 ). Although there was some evidence in previous research that some strata of small scale farmers do not mitigate against EIDs, this seems to be associated with a result of lack of risk awareness ( 16 , 18 ).…”

“…The intention has been to limit the role of water to act as a reservoir for influenza viruses, as well as reduce risk of transmission of between species (including humans), rather than prevent direct infection via pond or well water which is rare for H5N1. Nevertheless, direct infection via water has been reported ( 27 , 28 ) and risk increases with bathing in communal ponds or working in contaminated fish ponds, for example, both of which are common activities in rural Vietnam.…”

Defective Viral Particles Produced in Mast Cells Can Effectively Fight Against Lethal Influenza A Virus

“…Influenza A virus (IAV) is highly infectious, and causes significant morbidity and mortality worldwide ( Ly et al, 2016 ; Marinova-Petkova et al, 2016 ; Thomas et al, 2017 ). Highly pathogenic avian influenza virus (H5N1-HPAIV) has been categorized as a List A disease by the International Office of Epizootics (OIE).…”

Risk factors for avian influenza virus in backyard poultry flocks and environments in Zhejiang Province, China: a cross-sectional study

“…It has been demonstrated that contamination of poultry-related environments, including live poultry markets (LPMs) and backyard poultry flocks, is a major risk factor for human AIV [ 12 , 13 ]. Previous studies have reported differences in the poultry exposure to AIV between urban and rural areas.…”